Experimental Evaluation of Coffee Extraction Times: Integrating Statistical Analysis in Engineering Education

Resumen

The objective of this study is to analyze whether there are significant differences in coffee extraction times based on different commercial methods: filtration, evaporation, and immersion. To achieve this, a bifactorial experimental design was employed, using three types of coffee makers (Italian, French press, and drip filter) and three varieties of coffee from well-known brands in the Peruvian market. To ensure the validity of the statistical model assumptions, normality, homoscedasticity, and independence of residuals tests were conducted. The results showed a significant difference in extraction times with a 95% confidence level. Additionally, a post hoc Tukey-LSD analysis was applied with a significance level of ∝ = 0.05, identifying significantly different mean pairs and determining which method exhibited the longest extraction time. The findings indicate that the extraction method, particularly pressure and evaporation, is the primary factor influencing coffee preparation time, while the coffee brand has minimal impact. Among the evaluated extraction methods, evaporation, represented by the Italian coffee maker, proved to be the most efficient. In contrast, filtration, associated with the drip filter coffee maker, resulted in the longest extraction time. Meanwhile, immersion, represented by the French press, demonstrated greater stability in preparation times. This study not only contributes to the understanding of optimal coffee preparation but also serves as a practical case study in engineering education. The implementation of experimental methodologies, statistical data analysis, and process optimization in this work provides a useful didactic approach for disciplines such as chemical engineering, food engineering, and industrial engineering.